An earthquake, for the purpose of this disclosure, is defined as a sudden motion or trembling in the earth caused by the abrupt release of slowly accumulated strain. An earthquake swarm is a series of minor earthquakes, none of which may be identified as the main shock, occurring in a limited area and time, frequently in the vicinity of a volcano. A tremor is a minor earthquake, especially a foreshock or an aftershock. A foreshock is a tremor that commonly precedes a larger earthquake or main shock by seconds to weeks, and that originates at or near the epicenter of the larger earthquake. An aftershock is an earthquake which follows a larger earthquake or main shock and originates at or near the epicenter of the larger earthquake. Generally, major earthquakes are followed by a large number of aftershocks, decreasing in frequency over time. Such a series of aftershocks may last many days for small earthquakes or even many months for large earthquakes.
Large magnitude earthquakes that cause significant losses of life and property provoke the greatest attention. However, earthquakes of even greater magnitude may occur in relatively isolated areas which are principally of concern to seismologists.
Three parameters are important in assessing an earthquake (1) duration of the earthquake, (2) velocity of the surface movement, and (3) the rate of change of the velocity. In their potential for damage, these three factors are closely related. A very short earthquake of high velocity which has only one or two cycles of ground motion, is less damaging than an earthquake causing similar motion for many cycles. An earthquake with high acceleration but low velocity is less damaging than one causing higher velocities.
Earthquake intensity may be defined as a measure of the effects of an earthquake, notably in terms of people and structures. Earthquake intensity not only will be dependent upon the strength (or magnitude) of the earthquake, but also upon the distance from the epicenter. Intensity also will be markedly affected by local geology, by the numbers and kinds of structures in a given area, as well as the concentration of people within the affected area. Even the time of day may have a large bearing upon the effects, with large numbers of people assembled in factories, schools, offices, etc., during daytime hours.
The Richter scale classifies earthquakes as follows:
MagnitudeIntensity (Probable Effects)1Detectable only by instruments.2Barely perceptible, even near the epicenter.4.5Detectable within 20 miles of epicenter.Possible slight damage within a small area.6Moderately destructive.7A major earthquake.8A great earthquake.
Attempts have been made in the prior art to try to predict when and where an earthquake is likely to occur. These attempts have generally not been accurate in determining the time and location of an earthquake. The instant invention does not attempt to predict an earthquake but rather relies on the time differential between the time an earthquake occurs at the epicenter of the earthquake and the time it takes for an earthquake shock wave to arrive at a pager located at a finite distance from the earthquake's epicenter.
A search of the prior art did not disclose any literature or patents that read directly on the claims of the instant invention.